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![]() Hopper predicts prices for flights with 95 accuracy up to 1 year in advance. The primary advantage of Hopper over Thresher is the -jumping_execution flag, which enables goal-directed control-flow abstraction. You can watch a trip right in the app and we’ll send you a. This flag tells Hopper to try to achieve better scalability by "jumping" between relevant code regions rather than strictly following the program's control-flow. For better precision while jumping, use the -control_feasibility flag.įor example, to check for null dereferences in the Android app app.apk, you should run. hopper.sh -check_android_derefs -jumping_execution -control_feasibility -app app.apk. To compile/run the regression tests, do sbt test:compile and then. hopper.sh -regressions -jumping_execution. The core functionality of Hopper is an engine for refuting queries written in separation logic that is, showing that no concrete execution can satisfy the query. Hopper performs a form of proof by contradiction: it starts from a query representing a bad program state (such as a null dereference or out-of-bounds array access) and works backward in an attempt to derive false. SeriesGuide Android app - null dereference (fixed)ĬonnectBot Android app - null dereference (fixed) Here is a selection of bugs found using the assistance of Hopper/Thresher:Īndroid framework - write into all HashMap's (fixed) Hopper has several built-in clients (as described above) but writing your own clients is meant to be easy: just extend the Client class and write a checker that takes a program as input and emits separation logic formulae representing your client.įor more on Hopper and its predecessor tool Thresher, see our OOPSLA '15 paper, our PLDI '13 paper or the Thresher project page. Jython - array out of bounds error Troubleshooting #Hopper app android# Problem: Hopper compilation fails with missing dependency from walautil or droidel. Solution: Your walautil and droidel projects might be out of date. Try git pull sbt publishLocal in each directory. Problem: Hopper fails at runtime with a message like:. Solution: This happens when Hopper is run with the wrong version of Scala make sure you are using Scala 2.10. Problem: Hopper fails at runtime with a message like: : edu/colorado/walautil/cg/ImprovedZeroXContainerCFABuilder : Unsupported major.minor version 52.0. Solution: This happens when Hopper and walautil are built using different JDK versions. You may need to rebuild walautil and sbt publishLocal again.
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